Tag: waste

A rather simple Sankey diagram. It can be found on p. 195 of a study on Food Waste in Germany by ISWA, Stuttgart University comissioned by the Federal Ministry of Food and Agrriculture (BMEL). Flows are in million tons per year (averaged for the five-year period 2003 to 2007).

The yellow streams represent food delivered to individual housholds (“Haushalte”) as well as to commercial (large scale) users (“Grossverbraucher”) such as restaurants. The orange arrows show food waste (10 mo. tons p.a.). Note that individual households have a higher reject rate.

What happens to yard waste and biowaste in Germany? This Sankey diagram from a 2014 PowerPoint presentation titled ‘Flächendeckender Ausbau der Biotonne in Deutschland’ by Peter Krause and Rüdiger Oetjen-Dehne (u.e.c. Berlin) shows how these flows were distributed.

In 2012 there were 14.5 mio. tonnes of yard waste andd 6.6 mi. tonnes of bio waste (kitchen/food waste) were disposed of in Germany. Much of it was collected and treated or – such as in the case of yard waste – composted (7.8 mio. tonnes).

In addition to the absolute quantities the labels along the Sankey arrows show the average per inhabitant (kg/E, a).

A large potential is still in bio waste (orange-coloured arrow) being disposed of in regular household waste (“Restabfall”). Calls for separate collection of bio waste for energy recovery are being made.

The first diagram is for KVA Basel (waste incinerator Basel), the second for KVA Oftringen (waste incinerator Oftringen, Aargau). Basel is much larger (incinerated waste with energy content of 710 GWh in 2009) and serves an urban area. Oftringen is smaller and seems to be more of a regional waste incinerator (incinerated waste with energy content of 237 GWh in 2009).

Basel apparently sells off the heat to the district heating system or neighbouring industry (yellow arrow ‘Wäremexport’) and converts only a small fraction to electricity. Oftringen on the other hand sells off electric energy (43 GWh) with apparent losses (grey arrow 122,5 GWh).

A lot more to discover when comparing these two (and the other 27) Sankey diagrams.

Yesterday it became known that the European Commission would shelve their circular economy package of waste, recycling and incineration laws for now, in favour of an even more ambitious legislation to be presented by end-2015 (read here or here).

That led me to browse tweets using the hashtag #circulareconomy, and I ended up unearthing two nice Sankey diagrams…

The first one is by WRAP UK, showing the EU-27 material flows estimated in 2020. This is not for a specific type of material, but all material.

Flows are in million tonnes, with the 2020 values in blue, and the current (2010) figures in brackets below for comparison. There are three nodes: ‘Direct Material Input’, ‘Domestic Material Consumption’ and ‘Waste’. Unfortunately the size of the node icons is too large, and the flows are difficult to see. But still, this is a nice idea!

The main message is that in comparison to 2010, Europe could have 350 million tonnes of recycled material in 2020. Check out these Sankey diagrams by WRAP UK that basically convey the same messsage, but are less infographic.

Another Sankey diagram I found when browsing through the tweets was this one below. The title of the diagram is “How circular is th UK?”.

No values shown along the flows in this Sankey diagram, but neatly shaped circular flows. The question raised in the title is answered prominently with the message that 19% of the material in the UK is led in a loop (pink flow).

Energy flows in a waste incinerator facility of MVR-HH (‘Mullverwertung Rugenberger Damm’) in Germany are depicted as Sankey diagram on their website.

Flows are for 2013 in MWh per year (MWh/a). The hot red area is the boiler (‘Kessel’), followed by the turbine. Almost half of the energy is used as process steam and for district heating (‘Warmwasser Neugraben’). Losses branch out vertically.

From this presentation by Berlin-based consulting firm UEC comes the below Sankey diagrams on sorting of waste in a waste treatment facility in 2003.

No absolute values are given, only a percentage breakdown of the waste that is being treated.

After the first steps, the drum sieve (‘Siebtrommel’) splits the waste flow in three main fractions based on the size of the shreddered waste. The blue arrow are unsorted remains, the colored ones are recovered materials.

Only apparent flaw of this Sankey diagram is that the arrow labels show ranges for values. An accompanying table in the presentation has the minimum and maximum sorting quotas. Not clear which value was used for determining the arrow widths.

The study features two Sankey diagrams that show the present situation (2010) and a an alternative scenario, where much of the materials are recovered.

This is the current situation in which only 25% of the 3.16 Mt of waste (Building C&D Waste not considered) are recycled.

The authors explain that

“Each year Connecticut residents and businesses generate more than three million tons of munici pal solid waste (MSW, or “regular trash”). Currently existing recycling and reuse programs capture a portion of the value of Connecticut’s waste, while waste-to-energy facilities process and recover energy from most of the MSW that is not recycled. With our recycling infrastructure underutilized, and resource recovery facilities at capacity, there is vast potential to transform our management and processing systems to further unlock the economic potential of waste.”

The optimized scenario with much increased recycling of materials (almost 80%) is shown in this diagram:

Connecticut is looking into the environmental and economic benefit of a recycled materials econonmy.